Simplify the following expression: $x = \dfrac{7k}{3} - \dfrac{k}{4}$
Answer: In order to subtract expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $3$ and $4$ $\lcm(3, 4) = 12$ $ x = \dfrac{4}{4} \cdot \dfrac{7k}{3} - \dfrac{3}{3} \cdot \dfrac{k}{4} $ $x = \dfrac{28k}{12} - \dfrac{3k}{12}$ $x = \dfrac{28k -3k}{12}$ $x = \dfrac{25k}{12}$